Sorry, how does a time-based event not have anything to do with playing the spec that does the most DPS? And it's been Destro, forever. Don't feed people misinformation, especially people asking for advice on the best way to prepare themselves for gold. The attitude that I find cute is that someone asks for advice on 'what would be the best spec for challenge modes' and 'Is there any big differences between the specs?' and your response is 'it's about what class your playing'. Yeah man, that's the attitude right there. Go get 'em.

This is straight up wrong. Not only is Destro likely better AoE for the majority of groups out there but you want to be going into Rattlegore with full embers. As far as examples go that is a really bad one (you shouldn't be spec switching period).

I get that you probably enjoy demo — it's my favorite spec too — but are you serious? The OP professed to only recently leveling a warlock, and you're going to advise him to play a spec that's not only significantly more complex but also inferior in every respect? Ok.

You are feeding misinformation. You haven't carried 9/9 as demo (which I have), likely haven't gotten any realm best or world top 20 bests (which I have), and I'd wager haven't even tried demo in cm's. I've done 9/9 carries, including 3 mans as both specs, and have just overall done cm's a ton of times (selling carries mostly). They are about the same overall, in some cases slightly better, in some cases slightly worse. Hasn't been destro since forever, demo blew destro away by a mile until it got nerfed. I'll give you the complexity thing though, and agree that the op should just go destro since it's easier to play.

You are feeding misinformation. You haven't carried 9/9 as demo (which I have), likely haven't gotten any realm best or world top 20 bests (which I have), and I'd wager haven't even tried demo in cm's. I've done 9/9 carries, including 3 mans as both specs, and have just overall done cm's a ton of times (selling carries mostly). They are about the same overall, in some cases slightly better, in some cases slightly worse. Hasn't been destro since forever, demo blew destro away by a mile until it got nerfed. I'll give you the complexity thing though, and agree that the op should just go destro since it's easier to play.

I have done over 10,000 individual CM dungeons along with numerous world/US top times across a multitude of characters and specs. I know more than you, can't say it any plainer than that.